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A
gainst a background of growing demands from
the water and wastewater treatment industries
for submersible motor pumps that resist clogging,
deliver reliability and contribute to improving energy ef-
ficiency, KSB AG has developed a new centrifugal pump,
the Amarex-KRT F-Max (Figure 1) that addresses these
issues. Improved hydraulic system and motor performance
are delivered through the design of a new vortex impel-
ler and a motor that offers efficiencies currently calcu-
lated according to the same IEC 60034-2 measurement
method as that used for motors of dry-installed pumps.
In order to attain a pump’s optimum operating point,
it is essential to select the correct impeller and size of
impeller for the application. Whilst free-flow or ‘open’
impellers enable suspended solids in wastewater to pass
more easily through the pump than closed single channel
or multi-channel impellers, they do not compare favourably
when it comes to performance. It is for these reasons that
KSB has focused on designing an open impeller that can
achieve and even exceed the efficiency levels associated
with single-channel impellers. To improve overall efficiency,
KSB has looked to optimise the motors’ efficiency in an-
ticipation of future standards and market requirements is
in compliance with IE3.This has enabled KSB to markedly
reduce energy consumption.
Impeller development
The concept behind the design of the new pump is the
elimination clogging, a problem that causes inefficient
flows and possibly subsequent pump failure through the
presence of solids in wastewater. According to KSB the first
stage in finding a solution to clogging was to differentiate
between rigid and non-rigid solids. Michael Lebkuecher,
who headed the product management solid burden pumps,
comments: “Rigid solids need to have sufficient space in
the pump chamber for them to pass through the pump.
When it comes to non-rigid solids we have to ensure that
the presence of wet tissues and similar fibrous materials
do not form a mass. These problems were resolved, but
then the next challenge was to address overall efficiency.”
New impeller combines reliability
and efficiency
by Bryan Orchard
Growing demands from the water and wastewater treatment industries for
submersible motor pumps that resist clogging, deliver reliability and contribute to
improving energy efficiency, have led to KSB AG’s new centrifugal pump.
12
Chemical Technology • August 2016
Figure 1: The new Amarex KRT F-Max.
PUMPS AND VALVES